This proposal requests funds to acquire a Nikon A1 Confocal Laser Scanning Microscope with a PicoQuant FCS & FLIM Upgrade to support the investigation of molecular and biomolecular interactions and mechanisms at the University of Montana (UM). This system is capable of Fluorescence Lifetime Imaging (FLIM), Fluorescence Correlation Spectroscopy (FCS) and related single-molecule detection approaches, such as single-molecule Forster Resonance Energy Transfer (smFRET). Acquisition of instrumentation for FLIM, FCS and smFRET will significantly enhance the research capacity of the BioSpectroscopy Core Research Laboratory (BCRL) at UM. This Core supports the research activities of NIH-funded investigators participating in three centers at UM: NIH CoBRE Center for Biomolecular Structure and Dynamics (CBSD), NIH CoBRE Center for Environmental Health Science (CEHS), and Center for Structural and Functional Neuroscience (CSFN). The BCRL integrates their research activities with other UM Core research facilities (computational, X- Ray diffraction, and NMR) to provide a synergistic and multi-disciplinary approach to address fundamental questions in biophysics, biochemistry, molecular biology and biomedical sciences. The proposed microscope system will be incorporated into the BCRL, assuring access for UM and regional investigators. The acquisition of the requested instrument, capable of FLIM, FCS, and smFRET measurements, will have a significant and broad impact on biomedical research in the Rocky Mountain West. If funded, the requested instrument will replace the BCRL's existing time-resolved confocal fluorescence microscope, which is over a decade old, no longer supported by the manufacturer, and has severe loss of functionality (no scanning). The existing instrument can no longer meet the needs of research programs at UM with focuses in biomolecular structure and dynamics, environmental health and neuroscience. The proposed system will give biomedical investigators the tools to image and analyze the dynamics of functionally important interactions in model systems and cells. In this way, interactions and dynamics at the ensemble-average and single-molecule levels can be related to events at the cellular and tissue levels, thus providing new insights about functional interactions central to ou understanding of disease and the regulation of human biology.